Per NFPA 25, how often are foam concentrate samples collected?

• A. Daily
• B. Weekly
• C. Annually
• D. Biannually

Answer: (C)

Foam concentrate sampling is done to verify that stored foam concentrate remains usable and within specification for safe fire suppression. Concentrates can degrade, separate, or become contaminated over time, especially if storage conditions aren’t ideal. Checking a sample once a year provides a practical, regular check to confirm compatibility with the system and with the manufacturer's requirements. If the annual sample indicates degradation or changes beyond acceptable limits, the concentrate should be replaced before use; otherwise, it can continue to be used until the next yearly check. Daily, weekly, or biannual sampling is not the baseline requirement of NFPA 25, though specific manufacturer guidance might call for different intervals in certain conditions.